The difference between white and brown fat

White fat is the kind of fat that's common in the abdomen area of adults. It helps insulate the person and protect their internal organs. "It’s a good long-term energy source," Paul Harding said.

Brown fat is abundant in human babies and hibernating animals. People who live in very cold climates, such as Eskimos, have a little more brown fat than people living here in Ohio.

"As we get to be adults, we lose the majority of that brown fat except in certain areas. We have some around our shoulders and some around our aorta by our heart. Its function is to generate heat," Harding said.

Brown fat contains a lot of mitochrondria, the energy producers in animal and plant cells. Brown fat uncouples that energy process and "puts everything through what’s called an uncoupling protein to make heat instead of energy," he said.

This is the final story in a three-part series on patents at Miami. (Read part one and part two online at Miami News.)

Imagine if scientists could find a way to convert any type of cells into energy-burning brown fat cells that could metabolize blood sugar to generate heat.

Better yet, what if they could reprogram a cancerous tumor into those brown fat cells?

Paul Harding, associate professor of biology at Miami University, is investigating whether both scenarios might be possible in an animal.

If it works, Harding said, the breakthrough could have potential implications in the battles against obesity, diabetes and cancer.

"We've converted cancer cells in a dish into brown fat, so logically I think we can probably do it in an animal, too. We'll see. You don't know until you try," he said, cautioning the research is still preliminary.

Harding and former graduate student Zhenqing Zhou (Miami PhD '09) received approval on June 4 to patent the process, "Cell Transdifferentiation into Brown Adipocytes." That’s the conversion of any type of cell into brown fat in a culture dish.

This is Harding's third patent, his first at Miami. The research findings will be published in the December issue of the journal, Growth Factors.

Harding credits Darwal, who worked in his lab as an undergraduate zoology major, for laying the foundation for this area of fat research and "changing the whole focus of our lab."

Prior to that, the focus was on determining which part or parts of the growth factor were involved in making cells grow and divide.

Darwal wanted to make a model for cancer so she put the growth factor Heparin-binding epidermal growth factor (HB-EGF) and gene ADAM12, an enzyme that acts upon HB-EGF, together in cells.

"I'm sure everyone would expect those cells to grow and divide very rapidly, but they didn't," Harding said. "They turned to fat."

Harding thought Darwal made an error so he had her re-run the experiment. The findings came back the same.

These images demonstrate the successful conversion of cancer cells into brown fat in a culture dish after the cancer cells were combined with two genes, Heparin-binding epidermal growth factor (HB-EGF) and ADAM12, an enzyme that acts upon HB-EGF. Photo provided by Paul Harding.

"I was absolutely shocked," said Harding, who didn't see the spindle-shaped cells he expected. Instead, the cells were round and contained obvious fat.

"These serendipitous findings are sometimes very, very fruitful," he said.

Harding directed Zhou to determine what type of fat it was.

"Zhenqing did a fantastic job of identifying that it is brown fat," Harding said of Zhou, now a post-doctoral fellow at Washington University in St. Louis.

Darwal — who graduated from Lake Erie College of Osteopathic Medicine in June and is now doing a neurosurgery residency at Hackensack University and Saint Barnabas medical centers in New Jersey — said she's ecstatic the research is being recognized in Growth Factors.

The initial discovery of adipose (fat) tissue was "extremely intriguing," Darwal said. "It was incredible to think that our research may be able to change someone's life in the future."

Potential implications

Miami researchers are now trying to determine the functionality of the reprogrammed cells, which can produce glucose when stimulated.

"In theory, they should suck up glucose like it's going out of style," Harding said. "With that being said, we think there are tremendous therapeutic capabilities for Type 2 diabetes." The chronic condition affects the way a body metabolizes sugar, the main source of fuel.

The Centers for Disease Control and Prevention has called obesity a national epidemic and a major contributor to some of the leading causes of death, including heart disease, stroke, diabetes and some types of cancer.

Although targeting diabetes is one of Harding's hopes, the patented process actually is directed toward tumors, he said.

"We want to convert a tumor to brown fat," he said, noting they would study mice infected with tumors and placed in cold chambers to see if the tumors turn to fat.

Harding noted a possible downside: The viruses would also infect other tissues, such as the heart and liver. "Somebody else would need to assist us in how to target viruses to specific cells," he said.

Harding's third patent a charm for Miami

Paul Harding

Harding's two other patents stem from postdoctoral research done with a colleague at the Ohio State University. Both relate to connective tissue growth factor (CTGF). It plays an important role in many biological processes, but is critical in fibrotic disease such as lung and liver fibrosis, and various forms of cancer.

Harding conducted postdoctoral research at Children's Hospital in Columbus and at Ohio State before joining the biology department at Miami in 2001.

"When I was at Ohio State, I helped identify the most potent form that has been identified," he said. FibroGen, Inc., a research-based biotechnology company, purchased the rights to the patent Harding has with the researcher and hopes to develop it into a drug.

Harding strongly believes in involving undergraduate students in his research projects.

"I think it's all about grabbing these students when they are young, when they're in their freshmen and sophomore years," he said.

Darwal said her research experience had a lasting impact on her.

"Dr. Harding took me under his wing my freshman year with such enthusiastic guidance that it truly sparked my intellectual curiosity for the career path I ultimately took," she said.

Now other Miami undergraduate students are getting that same opportunity. Michael Markesbery, a junior zoology major from Cincinnati, and Katie Johnson, a junior biology major from Chillicothe, are working with Harding and Taylor on this brown fat research.

"It's incredible. If someone would have asked me coming out of high school if I would be doing this by junior year in college, I would have said there's no way," Markesbery said.

Markesbery will help present findings at the American Society for Cell Biology conference in New Orleans in December.

For Taylor of Middletown, the research will be a key part in working toward his doctorate in Miami's cell molecular structural biology program.

"Cancers are invasive cells that divide uncontrollably. We've found a way to make cells change what they are, and stop dividing," he said.

Taylor knows "a lot of things that work in dishes don't come to fruition in animals," but he's anxious to investigate that next step to determine if it might be possible.

Grant funding

Harding's research was supported by grant funding from the National Institutes of Health from 2009 through 2012. He recently applied for another NIH grant to continue the research.

He hopes the patent will help secure that funding, but also hopes to eventually draw attention from pharmaceutical companies.

While Harding is concerned about government research funding becoming more limited in recent years due to budget cuts, he thinks it can't hurt that this research could have potential implications with diabetes and cancer.

"Those are big areas in health today," he said, "so there should be a lot of interest."

The difference between white and brown fat

White fat is the kind of fat that's common in the abdomen area of adults. It helps insulate the person and protect their internal organs. "It’s a good long-term energy source," Paul Harding said.

Brown fat is abundant in human babies and hibernating animals. People who live in very cold climates, such as Eskimos, have a little more brown fat than people living here in Ohio.

"As we get to be adults, we lose the majority of that brown fat except in certain areas. We have some around our shoulders and some around our aorta by our heart. Its function is to generate heat," Harding said.

Brown fat contains a lot of mitochrondria, the energy producers in animal and plant cells. Brown fat uncouples that energy process and "puts everything through what’s called an uncoupling protein to make heat instead of energy," he said.

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